Inclosed electric fuse.



RN. OONANT.

INGLOSED ELECTRIC FUSE.

APPLICATION FILED JAN. 2, 1912.

1,081,214. Patented Dec. 9, 1913.

UNITED STATES PATENT OFFICE.

FRANKLIN N. CONANT,. OF NEWBURYPORT, MASSACHUSETTS, ASSIGNOR TO CHASE- SHAWMUT COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

INCLOSEI) ELECTRIC FUSE.

To'aZZ whom it may concern."

Be it known that I, FRANKLIN 1 CoNAN'r, a citizen of the United States, residing at Newburyport, in the county of Essex and State of Massachusetts, have invented an Improvement in Inclosed Electric Fuses, of which the following'is a specification.

This invention relates to inclosed electric fuses having a spring operated fuse-indicator, and has for its object the production of means to control the operation of the spring-indicator, whichinvolves an indicator controlling'element forming a part of a shunt which is adapted to be destroyed by an abnormal current passing through the shunt, and when destroyedto permit the indicator to operate; and also the produc: tion of an improved form of spring indicator.

In the present embodiment of my invention the indicator controlling means involves an indicator controlling-wire, which is attached at one end to one of the metallic endpieces of thefuse-case, and at the other end to the indicator, which latter isarranged in an aperture in the side of the fuse-case, and means within the case to electrically connect said indicator. controlling-wire with the other metallic end-piece of the fuse-case, thereby to form concealed shunt. The indicator controlling-wire is preferably of higher resistance material than the means to electrically connect said controlling-wire with the other end-piece of the fuse-case, said wire being preferably German silver andsaid connecting-means being a strip of copper, so thatthe controlling-wire will cer-.

tainly fuse and the. copper strip will not. The spring-indicator comprises essentially a case, an actuating-spring and an indicating-plug, said case fitting an aperture in the.

side of the fuse-case and containing both the actuatingepring and indicating-plug, and said indicating-plug adapted to be held by the indicator controlling-wire against the tension of the actuating-spring, so that when released-it will. be free to be expelled by the actuating-spring.

The'indicator controlling-wire is made as a loop, the end of the. loo passes through two small holes in the in icating- Specification of Letters Patent.

Patented Dec.9, 1913.

Application filed January 2, 1912. Serial No. 668,834.

the engagement therewith of the indicatingplug, said plug being held in engagement with said seat and against the tension of the actuating-spring by the indicator controlling-wire. J

In the present embodiment of my invention the inner end of the indicator controlling-wire passes through a small hole in the inner end of the indicator-case, and is connected with the indicating-plug, and the outer endv of the indicator controlling-wire is attached to one of the metallic end-pieces of the fuse-case, and the strip of copper which electrically connects said indicator controlling-wire with the other metallic endpiece of the fuse-case, is formed with a perforation at its inner end to receive the indicator-case and thereby to form an electrical engagement therewith.

Figure 1 is a central longitudinal section of an inclosed electric-fuse having airindicator, and means embodying my invention for controlling the operation of the indioa tor. Fig. 2 is a detail plan view of the controlling-means for the indicator shown in Fig. 1. Fig. 3 is a modified form of controlling-means, in connection with the spring indicator of Fig. 1, wherein the indicator controlling -Wire is made alike throughout its length.

10 represents the fuse-case; 12, 1-2 metallic caps or pieces arranged on its ends; 13 a fuse-strip arranged within the case and extended lengthwise thereof and connected at its ends to the end-pieces 12,. 12.

The fuse so far described is or may be bf any well known or suitable construction, and its case may be filled with any usual or suitable substance.

The spring indicator" here shown for the purpose of illustrating the invention embodies novel features. It comprises a cylindrical hollow metallic case 15 having a flanged head 14 at its inner endand having its outer end flared outwardly, as at 18, to

form aseat, an actuating-spring 16 adapted to be contained in the case but not usually connected therewith, and a plug 17 also adapted to be contained in the case but not usually connected with the actuating-spring. Said plug 17 is made as a circular disk, of a diameter larger than the diameter of the 4 opening in the case, thus adapting it to engage the seat 18. Said plug 17 is adapted to be held normally in. engagement with said seat and against the compressed actuatingspring 16, so that when released it will be expelled by the spring. Said plug is usually colored On th outside and serves as the in-' dicating-plug. Said indicator arranged in an aperture in the side of the case, whlch .may be located at any desired part thereof,

and the aperture is made of suitable size to receive the indicator-case with a snug fit, so as to preventthe escape of the gases around the case. It will be noted that the indicator-case and actuating-spring and indicatingeplug are entirely separate from each other, so that when the indicating-plug is released it will be expelled and the actuating-spring will likewise fly away from the case.

20 represents the indicator controlling- .wire, which is made of high resistance fusiblematerial, such as German silver. It is arranged within and extended lengthwise the fuse case. Its outer end is attached to I one of the metallic end-pieces 12., and its inner end is. passed through a small hole in the end of the indicator-case, and thence through the convolution's of the actuatingspring, and is, connected to the indicatingplug. In Fig. '1 it is composed of three strands, two. of which extend the full length, v so that the wire may be passed through two holes in the indicating-plug while the third strand terminates near the indicator, being coiled around the other strand, thereby to form a weakened portion adjacent the indicator In Fig.3, said indicator controllingwire is composed of but two strands, arranged to form a loop, the weakened portion a I being omittedf 25 represents a'strip of copper or equivalent low resistance material. Its outer. end

is connected to one of the end-pieces of the fuse-case and its inner end is perforated to receive the indicator-case l5, thereb to obtain electrical connection therewith. aid

strip serves toelectrically connect the"indij cator controlling-wire with the other end pieceof the fuse-case, thereby to form a concealed shunt, I Ordinarily when the fuse blows said strip- 25 will-remain intact as the high-resistance indicator controlling-wire is more easily fusible.

I claim:-

In an inclosed eiectric-ffuse, a fuse-case inetaliic end-pieces and i are in its side, a a

in the case and electrically connected with the end-pieces, a spring-indicator arranged in said aperture comprising a case, an actuating spring and plug engaging said spring, a high, resistance indicator controlling-wire arranged in the case and connected at one end with one of the end-pieces, its other end passing through a hole in the indicator-case and through the actuating-spring and attached to the plug, and a metallic conducting-strip arranged within the case and extended lengthwise thereof, having a perforation at its inner end to receive the indieating-ease and form electrical engagement therewith, its outer end being attached to the other end-piece of the fuse-case, substantially as described.

2. An inclosed filled fuse of the cartridge type having a non-conducting-casing, metaliic end caps and a main fuse-strip extending from one to the other end cap through the filling, said fuse case having a circular holewithln which is contained a metallic I indicator chamber rearwardly flanged so as to resist expulsion from the case, said indicator chamber contain ng a coiled spring held under tension by an indicatin disk which is held normally at the level 0 the exterior of the case by dicator controlling device consisting of a German silver wire attached to said disk, extending through the bottom of the indicatorchamber and thence along the inner wallof the casing to one of the end caps of 'the fuse, saidindicator controlling wire being electrically connected with a strip of low resistance metal extending from the in .dicator chamber to the other metallic endcase and adapted. to be eld compressed by said plug when thelatt'er is in engagement with its seat, and an indicator controllingwire connected to said plu to hold it in engagement with its seat wit the spring compressed, substantially as described.

4.- An inclosed electric-fuse, having a springindicator consisting of a case adapted to be arranged in.- an aperture in the side of' thefnse-case having a flanged head at its inner end and having its outer end flared outwardly to form-a seat, a plugto engage said seat, an actuating-spring containedin the case and held compressed by said plug o iatter is in engagement with its it, indicator controlling-wire made as the ina loop, the end of which passesthrongh a In testimony whereof, I have signed my hole in'the head of the indicator case and name to this specification, in the presence of through the actuating-spring and through two subscribing witnesses.

two holes in the indicator-plug, said indica- FRANKLIN N, CONANT.

5 tor controlling-wire holding the plug in en- Witnesses:

gagement with its seat with the spring com- B. J. N o ns, pressed, substantially as described. H. B. DAVIS.

, Copies of this petent may be obtained fordlve eents each, by addressing the "Commissioner of Iatente,

Washington, D. c." M 

